1. Field of the Invention
The present invention relates to a three-stage dust sampler, and more particularly, to a dust sampler for collecting IPM (inhalable particulate mass), TPM (thoracic particulate mass), and RPM (respirable particulate mass) dust samples.
2. Description of the Related Art
ISO, CEN and ACGIH have proposed three sampling efficiency criteria as new international standards, which classify dust entering the head airways as IPM (inhalable particulate mass), dust entering the bronchia as TPM (thoracic particulate mass), and dust entering the gas exchange region as RPM (respirable particulate mass). ACGIH is an acronym for the American Conference of Governmental Industrial Hygienists, ISO is an acronym for the International Standards Organization, and CEN is an acronym for the Comite Europeen de Normalisation.
Most samplers can only sample one type of dust; for example, the IOM sampler (IOM personal inhalable sampler, SKC Inc.) can only sample IPM; 10 mm nylon cyclone and the IOSH cyclone developed by the applicants can only sample RPM. The Model 8522 Respicon sampler from TSI (Thermo System Incorporated, St. Paul) is the only sampler that can sample the above three different dust types at the same time; this sampler meets the sampling efficiency criteria of ISO/CEN/ACGIH, but is large in size, is expensive, and these flow rates is not easy to be calibrated.
The Respicon makes use of three virtual impactors to sample the three kinds of dust, IPM, TPM and RPM simultaneously (Model 8522 operation and service manual). Previous researches show that when the Respicon sampler is used for sampling dust concentrations, the results are not identical to those of the TSI. The concentration of each kind of dust is lower than the true value.
Therefore, it is desirable to provide a dust sampler for collecting IPM (inhalable particulate mass), TPM (thoracic particulate mass), and RPM (respirable particulate mass) simultaneously using only one flow rate to operate and different operation principles.